SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2892697efa746cfc95924180dde03e9dffa4cbede5f602a9770be2321356b54b' 
  AND token = 'gRkZ+VOdIuB/p6DnU2UfQkizikldWBEcGtUj+OgtSYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}